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This study employed semi-structured interviews and Interpretative Phenomenological Analysis to explore experiences of on-time maturation in nine adolescent ballet dancers from across three vocational ballet schools in the United Kingdom. Two themes were identified as central to their experiences: 'A right and a wrong way to grow', and fitting in and moving forward. Instead of perceiving themselves as 'average' and experiencing a relatively easy pubertal transition, on-time dancers described unique challenges associated with a fluctuation between fitting in and not fitting in within their social context. The implications of on-time maturation in this context are complex and do not appear to follow the same trajectory as early maturing ballet dancers nor on-time non-dancers.

Purpose: The aim of the present study was to investigate the influence of players' relative age, maturation-related characteristics, and motor performance tests on two different stages of talent selection (regional and national level) in youth elite basketball. Methods: Relative age, maturation-related variables (height, weight, maturity offset, maturity timing) and motor performance (Countermovement jump, Standing long jump, Modified agility T-test, Linear sprint 20 m) of N = 68 male youth basketball players (Mage = 14.39 ± 0.28 years) were assessed during the initial selection tournament for the German U15 national team. Pre-selection biases regarding relative age and maturity timing on the regional level were investigated utilizing one-sample t-tests. Differences in relative age, maturation-related characteristics and motor performance between players selected (n = 27) and non-selected (n = 41) for the youth national team were examined via independent samples' t-tests and logistic regression analyses. Results: Strong pre-selection biases toward early-born and early-maturing players were confirmed on the regional level. Significant advantages in height and weight and higher values in maturity offset and maturity timing were found for selected players. Among the motor variables, only Countermovement jump performance was significantly better in selected players. When controlling for relative age and biological maturation regression models including motor performance variables did not significantly discriminate players' selection status. Conclusion: Coaches working in national, but also preceding selection stages (regional and club level) should raise their awareness to relative age and biological maturation when evaluating players' potential and current (motor) performance. [ABSTRACT FROM AUTHOR]

Physical activity (PA) during childhood and adolescence is important for the accrual of maximal peak bone mass. The precise dose that benefits bone remains unclear as methods commonly used to analyze PA data are unsuitable for measuring bone‐relevant PA. Using improved accelerometry methods, this study identified the amount and intensity of PA most strongly associated with bone outcomes in 11–12‐year‐olds. Participants (n = 770; 382 boys) underwent tibial peripheral quantitative computed tomography to assess trabecular and cortical density, endosteal and periosteal circumference and polar stress‐strain index. Seven‐day wrist‐worn raw acceleration data averaged over 1‐s epochs was used to estimate time accumulated above incremental PA intensities (50 milli‐gravitational unit (mg) increments from 200 to 3000 mg). Associations between time spent above each 50 mg increment and bone outcomes were assessed using multiple linear regression, adjusted for age, sex, height, weight, maturity, socioeconomic position, muscle cross‐sectional area and PA below the intensity of interest. There was a gradual increase in mean R2 change across all bone‐related outcomes as the intensity increased in 50 mg increments from >200 to >700 mg. All outcomes became significant at >700 mg (R2 change = 0.6%–1.3% and p = 0.001–0.02). Any further increases in intensity led to a reduction in mean R2 change and associations became non‐significant for all outcomes >1500 mg. Using more appropriate accelerometry methods (1‐s epochs; no a priori application of traditional cut‐points) enabled us to identify that ∼10 min/day of PA >700 mg (equivalent to running ∼10 km/h) was positively associated with pQCT‐derived measures of bone density, geometry and strength in 11–12‐year‐olds. Highlights: Accelerometry methods that are commonly used to assess free‐living, bone‐relevant physical activity (PA) are not well suited to measuring bone‐specific characteristics of PA (short bursts of high‐impact activity).Processing raw acceleration data using much shorter epochs (1‐s) and using incremental 50 mg intensity thresholds (rather than traditional, broad intensity thresholds) enabled a bone‐specific, beneficial intensity to be identified.The methods outlined provide a means for more precisely assessing free‐living bone‐relevant PA and permit the transparent and reproducible analysis of raw accelerometry data, which will enhance our ability to quantify dose‐response associations in the future. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the influence of maturation on match running performance in elite male youth soccer players. Methods: A total of 37 elite male youth soccer participants from an English professional soccer academy from the U14s, U15s, and U16s age groups were assessed over the course of 1 competitive playing season (2018–2019). Relative biological maturity was assessed using percentage of predicted adult height. A global positioning system device was used between 2 and 30 (mean = 8 [5]) times on each outfield player. The position of each player in each game was defined as defender, midfielder, or attacker and spine or lateral. A total of 5 match-running metrics were collected total distance covered, high-speed running distance, very high-speed running distance, maximum speed attained, and number of accelerations. Results: Relative biological maturity was positively associated with all global positioning system running metrics for U14s. The U15/16s showed variation in the associations among the global positioning system running metrics against maturity status. A multilevel model which allowed slopes to vary was the best model for all parameters for both age groups. In the U14 age group, advanced maturation was associated with greater high-speed running distance. However, maturation did not contribute toward variance in any of the indices of running performance in the U15/16s. In the U15/16 age group, significance was observed in the spine/lateral playing positions when undertaking actions that required covering distance at high speeds. Conclusions: Maturation appeared to have an impact on match-running metrics within the U14s cohort. However, within the U15/16s, the influence of maturation on match-running metrics appeared to have less of an impact. [ABSTRACT FROM AUTHOR]

The management of training load in youth team-sport athletes is important. There is, however, a lack of research on practitioners' perceptions and understandings of managing training load during this period and what this means in terms of maturational status and injury risk. This study aimed to investigate academy football practitioners' perceptions and understanding of training load, maturation and injury risk in young male footballers. Coaches, sports scientists, medical staff and key stakeholders from a professional football club academy in England participated in focus groups investigating their understanding and perceptions of training load, maturation and injury risk. A qualitative descriptive methodology utilising framework analysis was used to capture and better understand participants' views. Findings revealed that practitioners consider managing training load during adolescence to be comprised of, and mediated by, three key elements: club philosophy, factors inside the club's control (periodisation strategy; staff member practice), and factors outside the club's control (life load; growth and maturation). This study is an important addition to the current literature on managing injuries through the growth spurt by investigating how different stakeholders perceive training load, maturation and potential strategies to mitigate risk. [ABSTRACT FROM AUTHOR]

The pubertal transition can present an interesting paradox for the young dancer, with growth and maturation leading to improvements in some areas such as strength and power and detriment to others, such as flexibility and co-ordination. These challenges highlight the need to consider the interactions among biological, psychological and sociocultural factors during the pubertal transition in the context of the ballet environment. Awareness of these potential interactions will likely provide insights as to why some dancers successfully adapt to the challenges of puberty while others have greater difficulty. This review explores how we might extend existing biocultural models to the context of ballet in order to garner a greater understanding of the pubertal transition. Future research should explore the interactions among social, psychological and biological factors during puberty in adolescent ballet dancers in order to document important determinants of adaptive responses at puberty and to inform future endeavours aimed at promoting healthy pubertal transitions among young dancers.

This study investigated the associations between biological maturation status (classified using the Khamis–Roche method for the percentage of predicted adult height at the time of observation) and relative age (expressed as a decimal value relative to the difference between birth date and competition cut-off date) and the extent to which their relative selection biases existed across competitive age groups in an analysis of players within the Football Association of Ireland's (FAI) national talent pathway. The players assessed were either from the U13 FAI National Academy (n = 125), the Ireland U15 national team (n = 18), or the Ireland U16 national team (n = 16). A moderate to very large selection bias in favour of early maturing players was observed across all age groups, increasing in magnitude with successive age groups (p < 0.05). A total of 46–72% of players selected into the national talent pathway were early maturing; 0% of U15 and U16 players were late maturing. A relative age effect existed across all competitive cohorts (p < 0.05), although not increasing with chronological age and smaller in magnitude than maturation biases. A small positive correlation between relative age and absolute maturity status at U13 was observed, and an inverse correlation between relative age and relative maturity status at U15 (p < 0.01) was observed. There were no other significant correlations between relative or absolute maturity status and relative age. We encourage Football Associations to critically reflect upon their criteria for national talent squad selection; the current system diminishes the chances of selection for late maturing players. [ABSTRACT FROM AUTHOR]

To date, no studies have investigated the loads undertaken by elite youth footballers outside of their academy commitments. This study aimed to understand the load of English male academy football players' activity both inside and outside of the academy, as well as, how this load varies between age groups and days. Fifty-two male academy footballers were asked to record the duration, intensity and mode of moderate to vigorous physical activity undertaken outside of their academy training. These data were then combined with session Rating of Perceived Exertion load undertaken inside the academy over the corresponding period. Data were analysed using linear mixed models. The coefficient of variation (CV) was the between-subject standard deviation as a percentage of the mean. The variation of activity types players undertake outside the academy reduced with age. There was no significant difference in the 'outside of academy' load between age groups, but there was a significantly greater CV in the Under 15/16 (U15/16) group (CV = 164%) compared to the U12 (CV = 107%) and U13/14 (CV = 119%) age groups (P = 0.001). For the U12 group, there were no significant between-day differences in load outside of the academy or the combined (inside and outside) load. For the U13/14 and U15/16 groups, there were significant between-day differences in load outside of the academy, as well as, significant between-day differences in the combined load. Practitioners should consider how activities undertaken by players outside of the academy setting contribute to the weekly load periodisation and should modify their training schedules accordingly. [ABSTRACT FROM AUTHOR]

This study investigated the extent to which biological maturation selection biases existed according to playing position in national-level youth soccer. A total of 159 players from the U13 to U16 age groups in the Football Association of Ireland's national talent pathway and international representative squads had their relative biological maturity status assessed using the Khamis-Roche method for the percentage of predicted adult height at the time of observation. Players were categorised as goalkeeper (GK), central defender (CD), full-back (FB), centre defensive midfielder (CDM), centre midfielder (CM), centre attacking midfielder (CAM), wide midfielder (WM) or centre forward (CF). A series of one-sampled means t-tests were used to examine the degree to which biological maturation selection biases existed across playing positions. A non-parametric Kruskal-Wallis test was used to evaluate inter-positional differences. A small to very large selection bias in favour of early maturing players existed for GK (D = 0.7), CD (D = 1.65), FB (D = 0.49), CM (D = 0.62), WM (D = 0.78), and CF (D = 0.76) (p < 0.05). Maturational selection biases did not exist for CDM or CAM. Moreover, CD were significantly more advanced in maturation compared to FB, CDM and CAM (p < 0.05). This study supports the contention that maturation selection biases exist in youth soccer, but the magnitude of this bias is highly dependent upon playing position. The very strong maturity selection biases at the national level evidenced in this investigation highlight the need for Football Associations to explore strategies, such as futures programmes, to help to retain talented, yet late maturing athletes. [ABSTRACT FROM AUTHOR]